Bài giảng Medical Assisting - Chapter 29: The Immune System

Objectives 29-1 Spell, define, and correctly use the Key Terms in this chapter. 29-2 Define the terms infection, pathogen, and antigen. 29-3 List and describe the nonspecific body defense mechanisms. 29-4 Explain the signs and causes of inflammation. 29-5 Explain what is meant by specific body defenses.

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ChapterPowerPoint® to accompany Second EditionRamutkowski  Booth  Pugh  Thompson  WhickerCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Medical Assisting Chapter 291Objectives29-1 Spell, define, and correctly use the Key Terms in this chapter.29-2 Define the terms infection, pathogen, and antigen.29-3 List and describe the nonspecific body defense mechanisms.29-4 Explain the signs and causes of inflammation.29-5 Explain what is meant by specific body defenses.The Immune System2Objectives (cont.)29-6 Define B cells and T cells and describe their locations and functions.29-7 Explain the importance of MHC proteins.29-8 List the different types of T cells and describe their functions.29-9 List the different types of antibodies and tell how they differ.29-10 Explain how antibodies fight infection.29-11 Define complement and give its functions.The Immune System329-12 Explain the difference between the primary immune response and secondary immune response.29-13 Describe the function of a vaccine.29-14 Explain the four different types of acquired immunities.29-15 Describe how allergies develop.Objectives (cont.)The Immune System429-16 Explain how the AIDS virus affects the immune system.29-17 Identify the ways a person acquires AIDS.29-18 Define cancer and carcinogen.29-19 Explain how cancers are classified.29-20 Describe how cancers are diagnosed and treated.29-21 Describe the signs and symptoms of other common immune disorders. Objectives (cont.)The Immune System5Introduction Immune system - protects the body against Bacteria Viruses Fungi Toxins Parasites Cancer Click for Larger View6T and B Cell Activation7Defenses Against DiseaseInfection is the presence of a pathogen in or on the body Nonspecific defenses - mechanisms to protect us against pathogens in general Nonspecific DefensesSpecies Resistance Mechanical Barriers Chemical Barriers Fever Inflammation Phagocytosis 8Specific Defenses Against DiseaseSpecific defenses are called immunities and protect the body against very specific pathogens Lymphocytes and macrophages are the major white blood cells involved in specific defenses. Antibodies and complement are the major proteins involved in specific defenses 9Inflammation Signs: RednessHeatSwellingPainCauses:Injured or infected with a pathogen, inflammation can result 10Apply Your KnowledgeYour 18-year-old patient states that he thinks his right big toe is inflamed. What symptoms would you expect to see?11Apply Your Knowledge -Answer Redness, heat, swelling, and painYour 18-year-old patient states that he thinks his right big toe is inflamed. What symptoms would you expect to see?12B Cells & T CellsTwo major types of lymphocytesB Cells and T CellsRecognize antigens in the bodyT Cells Cell-mediated bind to antigens on cells and attack them directly B cells Respond to antigens by becoming plasma cell - make antibodies against the specific antigen 13Major Histocompatibility Complex (MHC) Before a T cell can respond to an antigen, it must be activated T cell activation begins when a macrophage ingests and digests a pathogen that has antigens Macrophage then takes some of the antigens from the pathogen and puts them on its cell membrane next to a large protein complex (MHC)T cells cannot be activated without macrophages and MHC proteins 14T CellsHelper T cells increase antibody formation, memory cell formation, B cell formation, and phagocytosis Memory T cells memory cells “remember” the pathogen that activated the original T cell person is later exposed to the same pathogen, memory cells trigger an immune response that is more effective than the first immune response 15AntibodiesIgG - recognizes bacteria, viruses, and toxins. It can also activate complement. IgA - found in secretions of the body such as breast milk, sweat, tears, saliva, and mucus-prevents pathogens from entering the body.IgM - very large - primarily binds to antigens on food, bacteria, or incompatible blood cells- activates complement.IgE - found wherever IgA is located- involved in triggering allergic reactions. 16Antibodies Fight InfectionAllow phagocytes to recognize and destroy antigens. Cause antigens to clump together which causes them to be destroyed by macrophages Cover the toxic portions of antigens to make them harmless. Activate complement Group of proteins in serum that attack Pathogens by forming holes in them. Attract macrophages to pathogens and can stimulate inflammation.17Immune ResponsePrimary immune response occurs the first time a person is exposed to an antigen slow takes several weeks to occur memory cells are made Secondary immune response occurs the next time a person is exposed to the same antigenvery quick usually prevents a person from developing a disease from the antigen 18Types of ImmunityNaturally acquired active - naturally exposed to an antigen - usually long lasting Artificially acquired - active-being injected with a pathogen (immunizations or vaccines) Naturally acquired passive - immunity through his mother - short-livedArtificially acquired passive - immunity when he is injected with antibodies - short-lived 19Apply Your KnowledgeAfter you have give an immunization to a 2-year-old, her mother asks you why this will work to prevent her from getting a disease.20Apply Your Knowledge -Answer Immunization is an artificially acquired immunity because a person develops this immunity by being injected with a pathogen and then subsequently making antibodies and memory cells against the pathogen. After you have give an immunization to a 2-year-old, her mother asks you why this will work to prevent her from getting a disease.21Major Immune System DisordersDiseases and disorders that challenge the immune system: (the following are the most significant) HIV Infections AIDS Cancer Allergies22Acquired Immune Deficiency Syndrome (AIDS)Caused by human immunodeficiency virus (HIV) infection Most common routes of transmission are through sexual contact, blood, or from mother to child during pregnancy or breast-feeding. Can have infection for years before developing any symptoms of this disease Less common routes of transmission are through accidental needle sticks, artificial insemination, and organ transplants.23Acquired Immune Deficiency Syndrome (AIDS) (cont.) AIDS virus affects the immune system Counts of CD4 cells are used to diagnose the stage of HIV infection. If below 200 patient has AIDS CD4 cells are types of T cells and are important for the functions of other components of the immune system. 24Acquired Immune Deficiency Syndrome (AIDS) (cont.)HIV Testing: The most sensitive test, and most expensive is called the polymerase chain reaction (PCR) Determines the number of HIV particles in a sample of blood. Useful in early diagnosis of HIV25Acquired Immune Deficiency Syndrome (AIDS) (cont.)AIDS Testing:ELISA – most commonly used testLess expensive than PCR test but less reliableCannot detect early HIV infectionsCounts of CD4 cells are used to diagnose the stage of HIV infection (CD4 cells are types of T cells)26Acquired Immune Deficiency Syndrome (AIDS) (cont.)Signs and Symptoms of AIDS:Low T cell countsFeverProfuse sweatingWeaknessWeight lossSwollen glandsFrequent infectionsSome rare forms of cancerA common form of cancer is called “Kaposi’s” sarcoma.27Apply Your KnowledgeHow can a patient contract HIV?28Apply Your Knowledge -AnswerMost common routes of transmission are through sexual contact, blood, or from mother to child during pregnancy or breast-feedingHow can a patient contract HIV?29CancerUncontrolled growth of abnormal cells Cells often form growths called malignant tumors200 different types of cancers are known Carcinogen - factor that is known to cause the formation of cancer30Cancer (cont.)The three most common forms of cancer: Breast Lung ColonLung cancer is the leading killer of all forms of cancer31Cancer CausesMostly unknownRisk factors:Suppressed immune systemRadiationTobaccoPrevention: Don’t smokeA factor that is known to cause cancer is called a carcinogen.32Cancer DiagnosisBiopsy - removal of tissues for examination CT scans Diagnostic tests Blood counts Analysis of blood chemistry X rays33Cancer TreatmentTreatment differs depending on:Type of cancerStage of cancerForms of treatment:Surgically removing the tumorChemotherapyRadiation therapy34Cancer Classifications Stage 0 - very early cancer. Cancer cells are localized in a few cell layers.Stage I - spread to deeper cell layers or some may have spread to surrounding tissues.Stage II - spread to surrounding tissues but is considered contained in the primary cancer site.35Cancer ClassificationsStage III - spread beyond the primary cancer site to nearby areas. Stage IV - spread to other organs of the body.Recurrent - Cancer cells have reappeared after treatment. 36Apply Your KnowledgeYour patient has a stage III cancer. Explain what stage III means.37Apply Your Knowledge -AnswerStage III means that the cancer has spread beyond the primary cancer site to nearby areas. Your patient has a stage III cancer. Explain what stage III means.38Allergies Allergic reaction is an immune response to a substanceAllergens - trigger of allergic responses Anaphylaxis - blood vessels dilate quickly causing blood pressure to drop too quickly for organs to adjust. This condition is life threatening.39Allergies (cont.)Allergic reactions involve IgE antibodies and mast cells. IgE antibodies bind to allergens, they cause mast cells to release histamine and heparinThese chemicals trigger allergic reactions. If a person is receiving allergy shots, he is being injected with tiny amounts of the allergen and reduces symptoms40 Chronic fatigue syndrome - a condition in which a person feels severe tiredness that cannot be relieved by rest and cannot be related to another illness Signs and symptoms:Severe fatigueMild feverSore throatTender lymph nodes in neck or armpitGeneral body achesDiseases and Disorders of the Immune System (cont.)41 Lymphedema - blockage of lymphatic vessels, which are needed to drain excess fluids from areas of the bodySigns:Swelling that lasts longer than a few daysSwelling that increases over timeDiseases and Disorders of the Immune System (cont.)42Lupus - an autoimmune disorder that affects few or many organ systems of the body Signs:Arthritis“Butterfly” rash on faceSensitivity to sunlightRenal failureHeadachesMental disordersDiseases and Disorders of the Immune System (cont.)43Rheumatoid arthritis - an autoimmune disorder in which a person’s immune system attacks joints of the body Signs:FatigueJoint painSwelling of joints – especially those in hands and feetBody achesCartilage destructionDiseases and Disorders of the Immune System (cont.)44Apply Your KnowledgeAs you are taking your patient to the exam room, you notice that she has “Butterfly” rash on her face. What disorder exhibits this sign?45Apply Your Knowledge -Answer LupusAs you are taking your patient to the exam room, you notice that she has “Butterfly” rash on her face. What disorder exhibits this sign?46Summary Medical AssistantKnowledge of the immune system will assist you in providing care for the patient with diseases and disorders of the immune system. You must have knowledge of this system when assisting the physician during the examination of a patient who is having problems with their immune system.47End of ChapterEnd of Chapter 48
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